DESCRIPTION: (Investigator's Abstract) Secondary cataract results from the proliferation of residual lens epithelial cells following extracapsular cataract surgery. Growth of these cells on the posterior capsule surface can eventually cause a clouding or distortion of the capsule and hence reduce vision. An agent that specifically destroys these cells at the time of primary cataract surgery could prevent the development of secondary cataract. HBI is currently developing the use of immunotoxins specific for lens epithelial cells, for the prevention of secondary cataract. The purpose of this proposal is to investigate new delivery methods for these immunotoxins, based on their adsorption or attachment to the intraocular lens. Immunotoxins associated with an intraocular lens would place the cytotoxic agent in immediate proximity with the target cell population, and increase residence time in the eye. These factors would lead to more efficacious killing, and at the same time allow for a substantial lowering of the clinical dose which would reduce patient exposure to the immunotoxin.